Production of microwaveable coated food products

ABSTRACT

A frozen, microwaveable, coated food product comprising: a core of cooked edible material having a weight equal to 15-95 wt. % of the food product; a fried coating that envelops the core of edible material and has a weight equal to 5-85 wt. % of the total weight of the food product, said coating comprising at least three coating layers, including an inner crumb layer, an outer crumb layer and a batter layer that separates the inner crumb layer from the outer crumb layer; wherein both the inner crumb layer and the outer crumb layer comprise a milled farinaceous dough extrudate containing 0.05-5 wt. % of added hydrocolloid.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/015,486, filed on Jan. 27, 2011, entitled PRODUCTION OF MICROWAVEABLECOATED FOOD PRODUCTS, the entire contents of which are incorporatedherein by reference.

TECHNICAL FIELD OF THE INVENTION

This invention relates to a method of production of coated food productswhich may be cooked or reheated using a microwave oven or using acombined microwave and conventional over, referred to collectively inthis specification as a microwave oven. The invention also relates toapparatus for carrying out the method and to food products made by themethod or using the apparatus. The invention relates particularly butnot exclusively to crumb coated products, particularly chicken nuggetsor other products wherein a meat, fish, poultry, vegetable, fruit,fungus materials or dairy products substrate is coated with a battercoating and one or more layers of crumb, wherein the products may becooked or reheated from a frozen state using a microwave oven.

BACKGROUND OF THE INVENTION

Use of a microwave oven for cooking or reheating coated products isproblematic because the substrate is heated from the inside by themicrowave radiation generating steam which may damage the batter andcrumb coatings. Conventional coated products are therefore unsuitablefor use in microwave ovens.

Many food materials, for example natural muscle of poultry, fish or redmeat or vegetable or processed foods contain a large percentage ofwater. Most fresh foods contain more than 60% water. Some of this wateris bound, that is tightly attached to the constituent cells. Theremaining mobile water is available and can be frozen. If a food productis frozen to a core temperature of between −1° C. and −30° C. or lowerand is placed and irradiated in a microwave oven, the microwave energywill be primarily absorbed by the frozen available water. Whereas inconventional cooking heat is applied from the exterior, in microwavecooking heat is generated from within. The process of heating can bevery rapid so that available water is converted into steam. When a foodproduct is allowed to stand after heating in a microwave oven, water cancontinue to be expelled from the product. This is particularlynoticeable for example when heating frozen fish muscle. The loss ofwater causes any food coating, particularly a batter, pastry orbreadcrumb coating to become soggy and unpalatable. In addition the coreof the substrate may become dry due to the loss of water.

WO 93/03634 describes a method of producing a coated foodstuff which maybe reheated by microwave irradiation, the method comprising: applying tothe foodstuff a predust; applying a batter to the predusted foodstuff;frying the battered foodstuff, and cooling the fried product.

WO 95/30344 describes a process for microwaveable coated food productscomprising the steps of predust application, batter application, crumbapplication, flash frying, freezing and packaging.

WO 97/03572 describes a process for microwaveable coated food products,such as chicken nuggets, comprising the steps of predust application,batter application, crumb application, flash frying, freezing andpackaging.

WO 2010/001101 describes a method of manufacture of a crumb coated foodproduct comprising the steps of: forming an aqueous mixture comprising:flour, sodium bicarbonate, optional additives and water; adding themixture into an extruder; adding an aqueous gelling agent to theextruder; extruding the resultant mixture at a temperature greater than100° C. to form an expanded porous product; drying the product, andmilling the dried product to form a crumb. The crumb so obtained isparticularly suitable for use in the preparation of coated food productsthat are cooked or reheated from a frozen state using a microwave oven.

SUMMARY OF THE INVENTION

The inventor has developed a method for the production of a frozencoated food product that can be reheated or cooked in a microwave ovento produce a ready-to-eat product with outstanding sensory properties,especially a crunchy coating in combination with a succulent moist core.

A first aspect of the present invention provides a method for productionof a frozen coated food product that can be reheated or cooked in amicrowave oven the method comprising the steps of: providing a portionof a solid or solidified substrate;

coating the portion with an aqueous precoating liquid to form aprecoated portion; applying a coating of bonding crumb to the precoatedportion to form a crumb coated portion;

applying a batter to the crumb coated portion to form a batter coatedportion;

applying a coating of coating crumb to the batter coated portion to forma breaded portion;

frying the breaded portion, thereby producing a fried coated portionhaving a core temperature in excess of 70° C.; and

freezing the fried coated portion by introducing said fried portion intoa freezer;

wherein the core temperature of the fried coated portion is not lessthan 50° C. when said fried portion is introduced into the freezer andwherein said core temperature is reduced to less than −15° C. usingcryogenic freezing.

According to a second aspect of the present invention, there is providedapparatus for carrying out the aforementioned method, said equipmentcomprising:

substrate forming apparatus for forming portions of a solid orsolidified substrate;

coating apparatus, arranged to receive the portions and to immerse theportions in a viscous aqueous coating composition to produce precoatedportions;

a first crumb applicator, arranged to receive the pre-coated portionsand to apply a layer of crumb onto the precoated portions to form crumbcoated portions;

a batter coating applicator, arranged to receive the crumb coatedportions and to immerse the crumb coated portions in a batter to producebatter coated portions;

a second crumb applicator, arranged to receive the batter coatedportions and to apply a layer of crumb onto the batter coated portionsto form multiple coated portions;

a fryer, arranged to receive the multiple coated portions and to immersethe multiple coated portions in hot oil to produce hot fried coatedportions;

a cryogenic freezer, arranged to receive and cryogenically freeze thehot fried coated portions.

DRAWINGS

The invention is further described by means of example but not in anylimitative sense with reference to the accompanying drawings, of which:

FIG. 1 is a flow chart illustrating the steps of the method;

FIG. 2 is a side elevation of apparatus in accordance with thisinvention;

FIG. 3 is a cross sectional view of a coating apparatus;

FIG. 4 is a cross sectional view of a crumb coating apparatus, and

FIG. 5 is a cut away perspective view of a fryer.

DETAILED DESCRIPTION OF THE INVENTION

Accordingly, a first aspect of the present invention relates to a methodof producing a frozen, microwaveable, coated food product, said methodcomprising the steps of:

providing a portion of a solid or solidified substrate;

coating the portion with an aqueous precoating liquid to form aprecoated portion;

applying a coating of crumb to the precoated portion to form a crumbcoated portion;

applying a batter to the crumb coated portion to form a batter coatedportion;

applying a coating of coating crumb to the batter coated portion to forma breaded portion;

frying the breaded portion, by contacting said breaded portion for atleast 100 seconds with hot oil having a temperature of at least 150° C.,thereby producing a fried coated portion having a core temperature inexcess of 70° C.; and freezing the fried coated portion by passing saidfried portion into a freezer; wherein the core temperature of the friedcoated portion is not less than 50° C., preferably not less than 60° C.when said fried portion enters the freezer and wherein said coretemperature is reduced to lower than −15° C. using cryogenic freezing.

The invention relates to a microwaveable frozen product, that is aproduct which has been cooked before freezing and which can be reheatedin a microwave oven or combination oven to give a satisfactory productwith a succulent core and crisp crumb coating. Products of thisinvention may be also reheated in a conventional thermal oven.

It has been found that the freezing conditions are important in order toproduce a frozen coated food product that, although it comprises a moistcore, can be heated in a microwave oven to yield a ready-to-eat hotproduct with a crunchy coating. More specifically, it has been foundthat the core temperature of the fried coated portion should be reducedvery quickly after frying, i.e. when the core temperature of the friedportion is still high. Although we do not wish to be bound by theory, itis believed that rapid freezing of the fried portion may enhance thestructural integrity of the product, may reduce formation of icecrystals and may reduce the size of any ice particles which may beformed within the product. If ice crystals are present in a batteredbreaded product they can become superheated in a microwave oven creatinghot spots in the core. Also migration of ice crystals on storage canlead to a build-up of localised ice which on heating can result inrelease of excessive moisture near to the surface coating.

In order to minimise ice crystal formation during freezing, the friedportion should be introduced in the freezer as quickly as possible afterthe frying. Accordingly, the core temperature of the fried coatedportion preferably may not decrease by more than 25° C., more preferablyby not more than 20° C. and most preferably by not more than 15° C.before the fried portion is introduced in the freezer, especially beforeit is contacted with liquid gas.

In a particularly preferred embodiment, the fried coated portion has acore temperature of more than 65° C., preferably more than 70° C. whenit is introduced into the freezer.

In a preferred embodiment, the core temperature of the fried portion isnot allowed to fall below the temperature specified when the substrateis introduced into the freezer.

In another preferred embodiment, the core temperature of the friedcoated portion is reduced at a very high rate from 60° C. to −15° C.Typically, this temperature drop is realized in less than 40 minutes,more preferably less than 30 minutes and most preferably less than 20minutes, dependent on the weight of the particles, dimensions of theparticles, temperature on entry and the number of particles passingthrough the freezer.

In use of the freezer that is employed in the present method, the coretemperature of the fried coated portion is typically reduced to lessthan −20° C. or even less than −22° C.

The cryogenic freezing of the fried coated portion in the present methodsuitably comprises contacting said fried portion with a liquid gas orvapourising liquid gas, more preferably cryogen, especially liquidnitrogen.

In a particularly preferred embodiment, the fried portion has a coretemperature of at least 50° C., more preferably of at least 60° C., evenmore preferably of at least 65° C. and most preferably of at least 70°C. when it is contacted with a cryogen.

The portions of solid or solidified substrate that are coated with theaqueous precoating liquid may be solid at ambient temperature or,alternatively, they may be liquid or paste-like at ambient temperature.In the latter case, for example. if the substrate is not solid atambient temperature, the substrate is cooled to a sufficiently lowtemperature to render it solid, before applying the precoating liquid.

The benefits of the present invention are particularly appreciated whenthe substrate contains an appreciable amount of water. During microwavereheating some of the water contained in the substrate will turn intosteam. Although the inventor does not wish to be bound by theory, it isbelieved that the fried coating of the present microwaveable product ispermeable to the steam that is generated during microwave reheating andhardly absorbs any of the steam, thereby retaining its crisp nature.Typically the substrate contains at least 15 wt. %, more preferably atleast 25 wt. % and most preferably at least 30 wt. % water. The watercontent of the core material normally does not exceed 90 wt %.

Examples of food materials that can be used to form substrate portionsinclude fish, meat, poultry, shellfish, shrimps, dairy products (e.g.cheese), ragu and combinations thereof. According to a particularlypreferred embodiment animal material selected from fish, meat, poultry,shellfish, shrimps and combinations thereof represents at least 40 wt.%, even more preferably at least 60 wt. % and most preferably at least80 wt. % of the uncoated portion of substrate.

The present method may suitably be used to produce coated food productsfrom portions of solid substrate have a weight in the range of about15-200 g. Preferably, the portions of solid substrate have a weight inthe range of about 10-50 g generally about 25 g.

Preferably the portion of substrate has a thickness not greater than 50mm, more preferably not greater than 25 mm, most preferably of notgreater than 15 mm. This allows sufficient penetration of microwaveradiation within a period of 2 to 3 minutes using the power available ina typical domestic microwave oven. Thicker portions may be partiallyheated, turned or further heated to completion if desired.

The portions of the substrate may be whole portions, for example wholemuscle portions such as individual steaks or fillets or larger pieceswhich may be cut into individual portions after cooking or reheating.Alternatively the pieces may comprise chopped or comminuted pieces, forexample, nuggets or minced products which may be reformulated intolarger portions. Use of pieces with uniformly sized and weighted coresis preferred.

The solid or solidified substrate may be extruded or ejected intoportions, e.g. on a wire mesh conveyor, using a die. The temperature ofthe extruded portions may be in the range of −6 to 6° C. preferably of−4 to −1° C. to stiffen the substrate to facilitate handling during thesubsequent processing steps.

The substrate, especially if it is composed of chopped or comminutedpieces, is preferably impregnated with an aqueous or particulatestabiliser composition, e.g. by soaking, permeation or injection (vacuumpulse injection) into the substrate prior to forming into portions.Examples of suitable stabiliser compositions can be found in WO97/03572, which is incorporated herein by reference for all purposes.The substrate may be impregnated with the stabiliser composition to theextent that the ingredients penetrate at least the surface layer. It isbeneficial if the region of the stabiliser impregnation extendsthroughout the substrate or at least impregnates the bulk of thesubstrate structure. Impregnation may be achieved by soaking, permeationor injection into the substrate prior to forming into portions. Vacuumpermeation is conveniently employed.

Application of the bonding crumb is facilitated by the use of theaqueous precoating liquid since the crumb particles will not adheresufficiently to a dry substrate or to each other to form a coherentshell encasing the substrate. Therefore, use of the precoating liquidhas the additional advantage that the crumb layer may adhere to thesubstrate providing a complete covering or shell surrounding thesubstrate to reduce the escape of water vapour and impede any ingress offat during frying.

The aqueous precoating liquid that is applied onto the substrate portiontypically contains at least 80 wt. %, preferably at least 90 wt. % ofwater. In order to minimize drip-off and to maximize adhesion of thecrumb, the precoating liquid is preferably viscous, and may have aminimum viscosity of 300 cP, measured using a Brookfield viscometer witha number 3 spindle at 60 rpm at 10° C. Even more preferably, saidviscosity lies within the range of 350-450 cP, most preferably in therange 380-420 cP when fully hydrated.

The aqueous precoating liquid preferably contains 0.1-5 wt. %, morepreferably 0.3-3 wt. % of dry matter.

A precoating layer serves as an additional barrier to loss of moisturefrom the substrate during subsequent microwave heating stage. Withoutwishing to be bound by theory it is believed that the precoating layerserves as a barrier to fat pickup by the core, avoiding impairment ofthe flavour of the core. Impregnation of the core with a stabilisercomposition as described herein before contributes to maintaining anoptimum moisture content of the core during cooking or reheating.

The aqueous precoating liquid may be applied onto the portion of solidor solidified substrate by immersing said substrate in a bath containingthe aqueous precoating liquid or by spraying or brushing said precoatingliquid onto the portion. Preferably, the precoating liquid is applied byimmersing it in a bath of precoating liquid, e.g. by passing the portionthrough such a bath with the help of a conveyor belt. The term “bath”refers to any convenient receptacle, trough or container suitable forholding a liquid.

Another important feature of the present method lies in the applicationof a bonding crumb layer before the application of a batter. This crumblayer is bound to the substrate by the aqueous precoating liquid andforms a stabilising thermal barrier underlying the batter and optionalouter crumb coating(s). This may provide a barrier to escape of moistureand ingress of oil during a prolonged frying stage. This crumb shellalso serves to protect the surface of the substrate from excessive localheating during frying.

Particularly good results can be obtained if the bonding crumb employedin the present method is a milled farinaceous dough extrudate containing0.05-5 wt. %, more preferably 0.1-3.% by dry weight of addedhydrocolloid. Crumb without an added hydrocolloid generally forms asoggy mass immediately upon mixture with water. The hydrocolloidcontained in the crumb may be any hydrocolloid which forms a sol whenmixed with water. Preferred hydrocolloids produce a crumb which retainsshape when in contact with water having a temperature of 20° C. for aperiod of 60 seconds.

The term “added hydrocolloid” as used herein refers to hydrophilicpolymers that are not naturally present in the farinaceous component ofthe dough extrudate and that are capable of increasing the viscosity ofan aqueous medium to which they have been added. These hydrophilicpolymers are suitably selected from polysaccharides, modifiedpolysaccharides and proteins.

The hydrocolloid used in the bonding crumb may be selected from naturalgums, modified gums, gelatine, pectin, alginate, modified starch, agar,carrageenan, furcellaran, arabinogalactan, xanthan, and combinationsthereof. Preferably, the hydrocolloid is selected from natural gums andcombinations thereof.

Examples of natural gums that may be employed as added hydrocolloid inthe milled farinaceous dough extrudate include guar gum, xanthan gum,locust bean gum, gum Arabic, tragacanth, gum karaya, gum ghatti andcombinations thereof.

Most preferably, the added hydrocolloid may be selected from guar gum,locust bean gum, xanthan gum and combinations thereof.

The bonding crumb employed in the present method typically has a massweighted average particle size of less than 2 mm. More preferably, thebonding crumb has a mass weighted average particle size of 0.1 to 1.5mm, even more preferably of 0.15 to 1 mm, and most preferably of 0.25 to0.9 mm.

The batter that is applied onto the crumb coated portion in accordancewith the present method preferably comprises, calculated by weight ofdry matter, 20-55 wt. % of starch; 20-55 wt. % of flour; and 3-20 wt. %of egg solids. Examples of batter formulations that may suitably beemployed in the present process are described in WO 96/32026. The starchcontained in the batter may be provided by a flour component or it mayhave been added as a purified starch ingredient, for example highamylose starch.

Typically, the batter has a viscosity of 200-1000 cP, more preferably of300-800 cP, most preferably of 500-600 cP, measured using a Brookfieldviscometer with a number 3 spindle at 60 rpm when it is applied to thecrumb coated portion.

The batter may be applied onto the crumb coated portion by an apparatuscomprising a bath containing the batter through which the crumb coatedportion is passed by means of a conveyor. A tempura applicator ispreferred, that is a bath containing circulating batter through which aconveyor passes. e.g. TempuDipper™ (CFS) although one may also use acurtain-type e.g. WetCoater™ (CFS) applicator or other convenientapparatus of a similar specification.

Advantageously, the coating crumb employed in the present method has alarger particle size than the bonding crumb. Preferably, the coatingcrumb has a mass weighted average particles size that is at least 50%higher than the mass weighted average particle size of the bondingcrumb.

The present method may suitably employ a crumb coating apparatus thatcomprises a first conveyor and a second endless conveyor located belowan end of the first conveyor, and passing beneath a flow of fine crumbparticles so that portions fall from the first conveyor onto a layer ofparticles on the second conveyor. The second conveyor may pass through acurtain of fine crumb falling onto the conveyor surface so that theportion falls onto the crumb causing the crumb to adhere to the surfacelayer of the aqueous precoating, and is then coated by the curtain offalling crumb particles. The apparatus may comprise a dispenser havingan outlet extending across of the conveyor to provide the curtain offine crumb extending across the path of the portions on the conveyor. Aroller may be located above the conveyor on the exit side to bear on thecoated portion to improve adhesion of the fine crumb.

Crumb may be applied in excess to the portion using a crumb applicatorfor example a CrumbMaster™ (CFS). The crumb coated portion may be passedthrough a roller to improve adhesion.

The total amount of aqueous precoating liquid, batter and crumb that isapplied onto the portion in the present method is preferably selectedsuch that, after frying, the fried portion has a weight that exceeds theweight of the uncoated portion of solid substrate by 25-100%, preferablyby 30-60%.

The one or more coatings of crumb together typically represent 5-80 wt.%, preferably 15-50 wt. % of the fried portion.

The breaded portion is fried to cook the substrate and coating layers.The period of cooking is preferably sufficient to completely cook thesubstrate preventing any health risk in the event that a frozen productis insufficiently reheated from the frozen state in a microwave oven. Acomparatively long period of reheating in a microwave oven isundesirable since the substrate is heated from the inside by themicrowave energy resulting in a loss of moisture. This may lead to a drycore and damage to the coating layers.

A homogeneous outer crumb coating, with none of the underlying batterlayer being exposed is advantageous to provide a uniformly brownedappearance after a prolonged period of frying. This may be compared to ashorter period of frying as commonly used for conventionally thermallycooked breaded products.

For conventional thermally cooked breaded products such as chickennuggets, a short period of frying for example 90 seconds or less hasbeen followed by a further period of cooking in a hot air oven. This isdisadvantageous for microwave cookable products because the core of thesubstrate may not be thoroughly cooked during reheating from the frozenstate. Prolonged heating of conventional products in a microwave ovenleads to excessive loss of moisture and consequent damage to the coatinglayers.

During the frying step the breaded portion, optionally after having beencoated with one or more additional crumb layers, is preferably contactedwith the hot oil for 120-300 seconds, more preferably for 130-240seconds, most preferably for 140-180 seconds.

The hot oil that is used for frying the breaded portion preferably has atemperature of 160-200° C., more preferably of 170-195° C. and mostpreferably of 175-190° C.

The oil employed preferably is a vegetable oil. The term “vegetable oil”encompasses non-modified vegetable oils, hydrogenated vegetable oils,fractions of vegetable oils (e.g. olein or stearin fractions),inter-esterified vegetable oils and combinations thereof. Pure rapeseedoil is preferred.

Preferably the core temperature of the fried portion is greater than 72°C., more preferably greater than 74° C.

The fried coating of the present food product—including all coatinglayers—preferably has an average thickness of 8. mm, more preferably of5 mm and most preferably of 3 mm dependent on the size of crumb used.

Frying in accordance with this invention is advantageous in comparisonto flash frying followed by hot air cooking as the latter may not give acoating with desired hardness without moisture loss from the core.

The breaded portion is suitably fried by immersing the breaded portionin the hot oil, e.g.

by passing it through a bath of hot oil by means of a conveyor belt. Thefrying apparatus preferably comprises a double layer of parallel endlessbelts both layers passing beneath the oil surface, a portion carried ona lower layer being prevented from floating during frying by contactwith an upper layer. The belt may comprise wire screens or otherperforated configurations.

The frozen products are suitably packaged for storage and distribution.Packaging under an inert atmosphere e.g. nitrogen is preferred.

The frozen product, may be reheated or cooked from the frozen statebefore use using an oven selected from: a microwave oven, a conventionaloven or grill, deep or shallow fried, or an oven using a combination ofmicrowave and conventional heating.

A further aspect of the invention relates to a microwaveable coated foodproduct that is obtained by a method as defined herein before. Mostpreferably, said food product is a frozen coated food product.

Yet another aspect of the invention relates to apparatus for producing afrozen coated food product as previously defined, the apparatuscomprising:

a substrate forming apparatus arranged for forming portions of a solidor solidified substrate;

a coating apparatus, positioned downstream of the substrate formingapparatus, arranged for immersing the portions in a viscous aqueouscoating composition to produce precoated portions;

a first crumb applicator, positioned downstream of the coatingapparatus, arranged for applying a layer of crumb onto the precoatedportions to form crumb coated portions;

a batter coating applicator, positioned downstream of the crumbapplicator, arranged for immersing the crumb coated portions in a batterto produce batter coated portions;

a second crumb applicator, positioned downstream of the batter coatingapplicator, arranged for applying a layer of crumb onto the battercoated portions to form multiple coated portions;

a fryer, positioned downstream of the second crumb applicator, arrangedfor immersing the multiple coated portions in hot oil to produce hotfried coated portions;

a cryogenic freezer, positioned downstream of the fryer, arranged toreceive and rapidly freeze the hot fried coated portions.

FIG. 1 is a flow chart illustrating stages of the method of anembodiment of this invention. The apparatus is shown in side elevationin FIG. 2 and component parts are shown in more detail in FIGS. 3 to 5.

In a pre-processing stage (1), pieces of chicken or other substrate arecut to an appropriate size or comminuted as required. The substratepieces are impregnated with a stabiliser composition, as described inExamples 1 and 2. A forming machine (20) is used. A conventional formingmachine may be arranged to extrude chicken substrate pieces having apredetermined thickness and one or more shapes. The pieces are extrudedonto a conveyor arranged to carry them to a tempura dipper containing anaqueous coating composition as described in Example 3.

The tempura coating apparatus is shown in FIG. 3. This comprises areservoir (30) for an aqueous coating composition or pre-gel (31). Afirst lower conveyor (32) carries pieces (35) beneath the surface of theaqueous composition. A second upper conveyor (34) prevents the pieces(35) from floating. This ensures complete coating of the pieces. Theupper and lower conveyors are disposed in parallel spaced relation toform a channel within which the pieces are located during coating.

A second lower conveyor (33) carries the substrate pieces out of thereservoir beneath the upper conveyor (34). The substrate pieces emergingfrom the reservoir pass under an air jet (36) to remove excess liquid.

Following application of the pre-gel or aqueous coating a coating ofcrumb fines is applied using a crumb applicator.

The fine crumb coated substrates are then passed through a tempurabatter applicator (6) to apply batter followed by application of theouter crumb. The batter mixture is prepared in a mixing tank with a highshear mixer and a heating system to maintain a temperature of 42° C. for30 minutes. The mixture is then transferred to a holding tank maintainedat 3° C. to 4° C. with the viscosity being adjusted as necessary beaddition of water before being pumped to the tempura-type applicator.

The batter coating may be applied using a tempura coating apparatus ofthe kind shown in FIG. 3. The substrate pieces which have been coatedwith aqueous coating and crumb fines are passed through a bath of thebatter using a wire mesh conveyor, so that complete immersion of thepieces is achieved.

A first layer of heavy grist crumb may be applied (7) to the battercoated product followed by a lighter grist crumb to infill between theheavy crumb particles (8). Alternatively, a single outer crumb layer maybe employed, particularly when using a large sized outer crumb.

Where two outer crumb layers are used, a first coating of outer crumbmay be applied using a conventional crumb applicator. The crumb ispreferably sieved to remove fines and small particles. A second coatingof outer crumb may be applied to ensure complete covering of thebattered substrate.

The crumb coated product is then passed (9) through an elongatereservoir containing heated oil to fry the products.

A frying time of 2 minutes 20 seconds was used although this may bevaried dependent on the weight and size of the particles. After fryingthe core temperature of the products was in the range 74° C.-85° C. Asmall loss of weight was observed due to loss of water from thesubstrate but this is mostly compensated for by an uptake of oil.

Following frying the hot fried products were directly without delaypassed using a conveyor into a cryogenic freezer so that the coretemperature of the fried products is reduced to a maximum of −25° C.,usually −30° C. to −35° C. or lower during a period of 30 minutes orless.

The construction of the fryer is shown in detail in FIG. 5. The elongatereservoir of the fryer contains rapeseed oil that is heated to aconstant temperature of 180 to 188° C. Pure rapeseed oil is employed.

The frozen products were packaged in hermetically sealed packages (12).The packing may be flushed with nitrogen (13) although this may not beused dependent on the required shelf life of the packaged products.

The crumb was prepared as disclosed in WO 2010/001101, the disclosure ofwhich is incorporated herein by reference for all purposes.

EXAMPLES Example 1 Stabiliser Composition

A stabiliser composition was prepared using the following ingredients:—

Ingredient % cellulose gum (Methocel ™ A4M) 15.0 modified starch(Thermflo ™) 24.0 polydextrose 40.0 xanthan gum 6.0 egg albumen 15.0Total 100.0

The composition was dissolved in water to produce a solution with aconcentration suitable to stabilise the particular substrate in use. Tothis end the dry powder mixture was partially hydrated in a tub and thenpoured into a bowl chopper. The bowl chopper was then run for two tothree minutes until the mixture was fully hydrated. The mixture can behydrated directly in the bowl chopper if required. Alternatively, thestabiliser may be hydrated using a high shear mixer fitted with ageneral purpose head.

This general purpose formula may be modified to increase its efficiencyin specific substrates. The above formula may be modified by addition ofcitric acid (up to 1%) and ascorbic acid (up to 2%) with thepolydextrose (for example Litesse II (Trade Mark)) being reducedaccordingly.

Example 2 Impregnation of Substrate with Stabiliser Composition

A chicken mixture for chicken dippers or nuggets was prepared with thefollowing composition which was prepared as a dry mixture, as analternative to use of a hydrated stabiliser composition. The stabiliserof Example 1 was used.

chicken emulsion 20% skin - 3 mm 18% chicken breast - 10 mm 50% water 2%rusk 2% stabiliser (Example 1) 5% seasoning 3% 100%

The chicken breast was chilled to −3° C. and minced using a 10 mm plate.After mincing, the temperature was 0-3° C. Water was added with mixing.A chicken emulsion comprising the following ingredients was added withmixing:

chicken skin 44% Water 44% soya isolate 11% Salt 1% 100%

The stabiliser in accordance to Example 1 was added and mixedthoroughly. Rusk was added with mixing following by seasoning. A drypowder flavouring was preferred. The composition was allowed to dissolvein use in water which was present in the substrate in order to form anaqueous stabiliser solution in situ. (Stage 1)

A vacuum was applied to the mixture to consolidate the structurefollowing which the chicken mixture was chilled to −3° C. (Stage 2) andformed into shaped pieces (Stage 3).

A similar procedure was used for other comminuted meat products. Largeparticulate cores may be manufactured using a similar method.

Example 3 Aqueous Coating Composition

The following mixture was prepared:

modified starch (Thermflo) 35% thickener (Methocel A4M) 25% xanthan gum25% egg albumen 15% 100%

The mixture was dissolved in water to form a 1% solution using a CFSScanbrine mixer with paddle agitation. The solution was left to standfor 24 hours to form a fully hydrated gel or viscous solution.

A pump is necessary to run the machine but after a short while bubblesmay form in the gel solution in the applicator. To prevent this problemfood grade anti foaming agents can be used. Polydimethylsiloxane ispreferred but methylphenylpolysiloxane or polyethylene glycol can beused.

Example 4 Batter Coating Composition

A batter coating composition was prepared by mixing the followingingredients:

Ingredient % Soya flour (Hisoy) 31.0 high amylase starch (Hylon 7) 48.0cellulose gum (Methocel A4M) 2.0 whole egg (Henningsen W1) 13.0 D-xylose03.0 monosodium phosphate 1.90 ammonium bicarbonate 0.7 gluconoD-lactone 0.7 sodium acid pyrophosphate 0.3 alphya-amylase 0.1 100.00

The batter was mixed in batches using a Silverson DX high shear mixer ona gantry with a slotted disintegrating head. Batches were mixed in theratio of 25 kilos water to 12.5 kilos dry batter powder in a vat with adiameter of 68 cm. Thereafter, the mix was diluted as required forexample to give a ratio of water:powder of 2.4:1.

In full scale production the batter ingredients were mixed in a ratio ofwater:powder of 2.4:1 using two 200 litre stainless steel vessels linkedby a pump and an inline Silverson mixer with a high shear slotteddisintegrating head. One tank was fitted with a paddle and was filledwith water at 15-20° C. The dry ingredients were added to the water andwetted by rotation of the paddle. The second tank was fitted with acooling jacket and a return pipe to the first vessel. The batter mixturewas circulated through the high shear head until a temperature of 42° C.was reached by mechanical heat transfer. External heating may beemployed to avoid a tendency to over shear the starch. When 42° C. wasreached, the mixing and enzymolyis were complete. The batter wastransferred to the second vessel and cooled. A heat exchanger may beused to cool the mixture. After cooling, the batter was pumped into atempura type batter applicator.

The viscosity in the batter mixture was in the range 550-650 cP asmeasured by a number 3 spindle at 60 rpm. The batter was found to give agood rate of pickup and a crisp coating after frying.

Example 5 Preparation of Crumb

A hydrocolloid containing crumb was produced by extrusion of afarinaceous dough mixture as disclosed in WO2010/001101.

A flour composition was prepared as follows:

flour mixture 96.4% sodium bicarbonate (Bex baking powder) 2.0% glycerylmonostearate 0.6% salt 1.0% 100.0%

The gelling agent was as follows:

guar gum 67.00% sodium metabisulphite 33.00% 100.00%

The gelling agent was hydrated at 3% in 97% water. This was done using ahigh shear mixer. The hydrated mix was left to stand for at least 12hours after mixing.

Hutchinsons Golden cake flour (150 kg per hour) was mixed with water (35kg per hour) to form a slurry. The slurry was fed into a Clextraltwin-screw extruder. The hydrated gelling agent was injected into theflat zone of the extruder in an amount of 7.5% (13.88 kg per hour). Theextruded mixture was chopped into pieces and allowed to expand to form abubble. When dried to a moisture content of 2% w/w the bulk density was150 g·l⁻¹. The bubble was dried and milled and the resulting crumb wasshort and crisp. Application to a food substrate made a hard crumbcoating. The dried bag product had a shelf life exceeding 12 months.

After extrusion the extrudate may be milled and sieved to produce crumbparticles of the desired size which passed through a 4 mm sieve but wereretained by a 3 mm sieve. Crumb fines which passed through a 1 mm sieveresultant from milling of larger crumb particles were used inapplication to the substrate pieces coated with the aqueous coating.

Example 6 Production of Microwaveable Frozen Chicken Nuggets

Stabilised substrates prepared in accordance with Example 2 were coatedwith an aqueous coating composition as described in Example 3. A finecrumb coating as described in Example 5 was applied followed by a battercoating as described in Example 4.

Next a coating of the coarse crumb of Example 5 (particle size 3-4 mm)is applied using a CrumbMaster applicator (24) manufactured by CFS,Bakel, Netherlands.

The crumb applicator is shown in cross sectional view in FIG. 4.

An endless conveyor (40) passing over a guide plate (46) receivesbattered substrate pieces (41). A supply of 2 mm crumb (42) contained inhopper (43) has an outlet extending across the width of the conveyor(40). Additional crumb may be added through inlets (51). Excess crumb(45) passing through the chain link conveyor (40) is collected by screwlift (47) and ejected into the top (48) of the hopper (43). A roller(44) serves to compress the crumb onto the surface of the substrateparticles. An air blower (49) removes excess crumb from the coatedparticles, following which the particles (50) pass to a second crumbapplication station (Stage 8) for application of lighter grist crumb forinfill between the larger crumb applied in Stage 7. The configuration ofthe batter crumb applicator (25) is similar to that of the first crumbapplicator (24).

Following application of the first and second crumb layers the coatedsubstrates enter a fryer (26). The construction of the fryer is shown indetail in FIG. 5.

Heated oil (60) contained in an elongate reservoir (61) is heated to aconstant temperature of 180 to 188° C. Pure rapeseed oil is employed.

Parallel upper and lower conveyors (62, 63) prevent the substrate piecesfrom floating during passage through the fryer. A frying time of 2minutes 20 seconds may be used although this may be varied dependent onthe weight and size of the particles. After frying the core temperatureof the particles was in the range 74-85° C. A small loss of weight wasobserved due to loss of water from the substrate but this is mostlycompensated for by an uptake of oil.

Following frying the fried products are transferred directly and withoutdelay to a freezing station.

The fried products when removed from the heated oil had an externaltemperature of about 180° C. and a core temperature of about 90° C. Theproducts were transferred by the conveyor into a cryogenic freezerduring a period of not less than 2 minutes. During this time thetemperature of the outer crumb was reduced due to contact with theatmosphere but the temperature of the core may rise for a brief perioddue to transfer of heat from the outer crumb layer to the core. On entryinto the freezer the core temperature may be between 70° C. and 100° C.,generally about 75° C.

The fried product of Stage 9 was immediately transferred in Stage 10 toa cryogenic freezer which reduced the core temperature to a maximum of−25° C., preferably −30° C. The time from the removal from the fryer toentry into the freezer was less than 2 minutes.

The transfer from the fryer to the freezer is arranged so that the coretemperature of the product was reduced from 75° C. to −30° C. during aperiod not longer than 15 minutes

1. A method of producing a microwaveable, frozen, coated food productsaid method comprising the steps of: providing an edible portion of asolid or solidified substrate as a core of edible material; coating thecore of edible material with aqueous precoating liquid which is ahydrated gel or viscous solution that comprises water and dry matterdissolved in the water to form a precoated portion; applying a coatingof bonding crumb to the precoated portion to form a crumb coated portionwhere the bonding crumb is bound to the substrate by the aqueousprecoating liquid; applying a coating on top of the bonding crumb;wherein forming a coating coated portion; applying a coating of coatingcrumb to the coating coated portion to form a breaded portion; fryingthe breaded portion in a fryer by contacting said breaded portion withhot oil having a temperature of at least 150° C., thereby producing afried coated portion having a core temperature in excess of 70° C.;directly transferring the fried coated portion from the fryer into acryogenic freezer, and cryogenically freezing the fried coated portion;wherein the core temperature of the fried coated portion is not lessthan 60° C. when said fried coated portion is introduced into thecryogenic freezer and wherein said core temperature is reduced to lessthan −15° C. in the cryogenic freezer; wherein the method yields afrozen, microwavable, core of edible material and a breaded portion. 2.The method according to claim 1, wherein the fried coated portion has acore temperature of not less than 65° C. when it is introduced into thefreezer; and guar gum containing milled dough extrudate is used in boththe bonding crumb and the coating crumb.
 3. The method according toclaim 1, wherein the fried coated portion has a core temperature notless than 70° C. when it is subjected to cryogenic freezing and whereinthe step directly transferring the fried coated portion from the fryerinto a cryogenic freezer is done within two minutes.
 4. The methodaccording to claim 1, wherein the fried coated portion is contacted witha cryogen until the core temperature of the portion is less than −22° C.5. The method according to claim 1, wherein the core temperature of thefried coated portion does not decrease by more than 25° C. before thefried portion enters the freezer.
 6. The method according to claim 1,wherein the aqueous precoating liquid has a minimum viscosity of 300 cP,measured using a Brookfield viscometer with a number 3 spindle at 60 rpmat 10° C. and wherein the aqueous precoating is formed by dissolving thedry matter in water and allowing the solution to stand.
 7. The methodaccording to claim 1, wherein the bonding crumb contains at least 80weight percent of a milled farinaceous dough extrudate containing 0.05to 5 weight percent of added hydrocolloid.
 8. The method according toclaim 7, wherein the hydrocolloid is selected from the group consistingof guar gum, locust bean gum, gum Arabic, tragacanth, gum karaya, gumghatti, xanthan gum, and mixtures thereof and wherein the step directlytransferring the fried coated portion from the fryer into a cryogenicfreezer is done within two minutes.
 9. The method according to claim 1,wherein the batter comprises, calculated by weight of dry matter, 20 to55 weight percent starch; 20 to 55 weight percent flour; 3 to 20 weightpercent egg solids.
 10. The method according to claim 1, wherein, thebatter, when it is applied to the crumb coated portion, has a viscosityof 200 to 1000 cP measured using a Brookfield viscometer with a number 3spindle at 60 rpm.
 11. The method according to claim 1, wherein thetotal amount of aqueous precoating liquid, batter and crumb that isapplied to the portion is such that, after frying, the fried portion hasa weight that exceeds the weight of the uncoated portion of solidsubstrate by 25 to 100%.
 12. A microwaveable, coated food productobtained by a method according to claim
 1. 13. The method according toclaim 1, wherein the core temperature of the fried coated portion is notless than 60° C. when said fried portion is introduced into the freezerand wherein said core temperature is reduced to less than −15° C. inless than 40 minutes.
 14. The method according to claim 1, wherein thecore temperature of the fried coated portion does not decrease by morethan 20° C. before the fried portion is contacted with a cryogen in thefreezer and wherein the fried coated portion is contacted with a cryogenuntil the core temperature of the portion is less than −20° C.
 15. Themethod according to claim 1, wherein transfer of the fried coatedportion from the fryer to the freezer is arranged such that the coretemperature of the fried coated portion is reduced from a temperature of75° C. or greater to a temperature of −30° C. or less during a periodnot longer than 15 minutes and wherein the batter, when it is applied tothe crumb coated portion, has a viscosity of 500 to 600 cP measuredusing a Brookfield viscometer with a number 3 spindle at 60 rpm.
 16. Themethod according to claim 1, wherein the total amount of aqueousprecoating liquid, batter and crumb that is applied to the portion issuch that, after frying, the fried portion has a weight that exceeds theweight of the uncoated portion of solid substrate by 30 to 60% andwherein the substrate potion has a weight in the range of about 15 to200 g and a thickness of up to 50 mm.
 17. A method of producing amicrowaveable, frozen, coated food product said method comprising thesteps of: providing an edible portion of a solid or solidified substrateas a core of edible material; coating the core of edible material withaqueous precoating liquid which is a hydrated gel or viscous solutionthat comprises water and dry matter dissolved in the water to form aprecoated portion; applying a coating of bonding crumb to the precoatedportion to form a crumb coated portion where the bonding crumb is boundto the substrate by the aqueous precoating liquid; applying a coating ontop of the bonding crumb; wherein forming a coating coated portion;applying a coating of coating crumb to the coating coated portion toform a breaded portion; frying the breaded portion in a fryer bycontacting said breaded portion with hot oil having a temperature of atleast 150° C., thereby producing a fried coated portion having a coretemperature in excess of 70° C.; directly transferring the fried coatedportion from the fryer into a cryogenic freezer, and cryogenicallyfreezing the fried coated portion; wherein the core temperature of thefried coated portion is not less than 60° C. when said fried coatedportion is introduced into the cryogenic freezer and wherein said coretemperature is reduced to less than −15° C. in the cryogenic freezer;wherein the method yields a frozen, microwavable, core of ediblematerial and a breaded portion; and guar gum containing milled doughextradite is used in both the bonding crumb and the coating crumb. 18.The method of claim 17, wherein the step directly transferring the friedcoated portion from the fryer into a cryogenic freezer is done withintwo minutes.
 19. A method of producing a frozen, microwaveable, coatedfood product, said method comprising the steps of: providing a portionof a solid or solidified substrate coating the portion with an aqueousprecoating liquid to form a precoated portion; applying a coating ofbonding crumb to the precoated portion to form a crumb coated portion;applying B batter to the crumb coated portion to form a batter coatedportion; applying a coating of coating crumb to the batter coatedportion to form a breaded portion; frying the breaded portion bycontacting said breaded portion for at least 100 seconds with hot oilhaving a temperature of at least 150° C., thereby producing a friedcoated portion having a core temperature in excess of 70° C.; andfreezing the fried coated portion by introducing the fried portion intoa freezer; wherein the core temperature of the fried coated portion isnot less than 50° C. when the fried portion is introduced into thefreezer and wherein the core temperature is reduced to less than −15°C., using cryogenic freezing.
 20. The method of claim 19, wherein thefried portion is introduced into the freezer within 2 minutes or lessafter completion of the frying step.